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CHICAGO — Has the human lifespan been pushed as far as it can possibly go? Researchers in Chicago are throwing cold water on the idea that people may be able to live dramatically longer lives in the coming decades.
The study, led by S. Jay Olshansky and published in the journal Nature Aging, suggests that the rapid gains in life expectancy seen during the 20th century are now slowing significantly, and radical life extension beyond current levels is unlikely in this century. In simpler terms, scientists believe modern medicine has pushed the human lifespan to around 100 years, but it likely won’t go any higher than that in the future.
“Most people alive today at older ages are living on time that was manufactured by medicine,” says Olshansky, a professor of epidemiology and biostatistics at the University of Illinois Chicago, in a media release. “But these medical Band-Aids are producing fewer years of life even though they’re occurring at an accelerated pace, implying that the period of rapid increases in life expectancy is now documented to be over.”
Throughout the 1900s, life expectancy at birth in high-income countries surged by about 30 years, largely thanks to advances in public health and medicine. This remarkable progress led some scientists and futurists to predict that the trend would continue, with some even suggesting that most babies born today could live to see their 100th birthday.
However, Olshansky’s team found that improvements in life expectancy have actually slowed in the world’s longest-lived populations since 1990. They examined demographic data from eight countries with the highest life expectancies (Australia, France, Italy, Japan, South Korea, Spain, Sweden, and Switzerland), along with Hong Kong and the United States, spanning from 1990 to 2019.
The researchers discovered that the pace of life expectancy gains has slowed in every population studied except for people in Hong Kong. Even more tellingly, the most recent decade showed slower improvements compared to the 1990s across the board. In most of these countries, annual increases in life expectancy have dropped below 0.2 years – a far cry from the 0.3 years per year that defined the “radical life extension” of the 20th century.
Perhaps most surprisingly, the study suggests that it’s becoming increasingly difficult to push life expectancy any higher than it already stands. The researchers found that the reduction in overall mortality needed to raise life expectancy by just one year has actually increased since 1990. In other words, it now takes a larger improvement in survival rates to achieve the same gain in life expectancy.
“Our result overturns the conventional wisdom that the natural longevity endowment for our species is somewhere on the horizon ahead of us — a life expectancy beyond where we are today,” Olshansky continues. “Instead, it’s behind us — somewhere in the 30- to 60-year range. We’ve now proven that modern medicine is yielding incrementally smaller improvements in longevity even though medical advances are occurring at breakneck speed.”
The study also casts doubt on predictions that most people born today will live to 100 and possibly even further. Based on current trends, the researchers estimate that, at most, about 15% of women and 5% of men in any given population will reach the century mark – and even that figure may be optimistic.
Despite the apparent bad news, the Chicago team urges people to stay positive about the future. While their findings may be a roadblock to seeing your 200th birthday, this research isn’t the final word on the subject.
“This is a glass ceiling, not a brick wall,” Olshansky contends. “There’s plenty of room for improvement: for reducing risk factors, working to eliminate disparities and encouraging people to adopt healthier lifestyles – all of which can enable people to live longer and healthier. We can push through this glass health and longevity ceiling with geroscience and efforts to slow the effects of aging.”
Paper Summary
Methodology
The researchers analyzed life expectancy data and mortality rates from national databases, focusing on countries with the longest-lived populations. They used demographic techniques to calculate various measures of lifespan, including “life table entropy” (a measure of the dynamics of survival patterns) and “lifespan inequality” (which looks at the variability in ages at death). By examining how these measures changed over time, the team could assess whether life expectancy improvements were accelerating, decelerating, or holding steady.
Key Results
The study found that annual increases in life expectancy have slowed since 1990 in nearly all populations studied. The researchers also observed that it’s becoming harder to achieve further gains – the mortality reductions needed to raise life expectancy by one year are now larger than they were in the past. Additionally, the analysis showed that lifespan inequality (the variation in ages at death) has been decreasing, suggesting a compression of mortality into a narrower age range rather than a uniform shift to later ages.
Study Limitations
The study primarily focuses on high-income countries with already long-lived populations, so the findings may not apply to developing nations that still have room for rapid life expectancy gains. Additionally, while the researchers consider potential future medical advances, the unpredictable nature of scientific breakthroughs means long-term projections always carry some uncertainty.
Discussion & Takeaways
The researchers argue that we’re approaching a “second soft limit” to longevity – one that’s less responsive to disease treatment but could potentially be overcome by interventions that slow the biological aging process. They suggest that rather than assuming continued rapid increases in lifespan, policymakers and industries (like insurance and retirement planning) should adjust their expectations. However, they also emphasize that this isn’t a pessimistic view – rather, it’s a celebration of how far human longevity has already come.
Funding & Disclosures
The study received funding from the National Institute on Aging, the National Institute of Child Health and Human Development, and the National Institute of General Medical Sciences. The American Federation for Aging Research provided funding for open-access publication. The authors declared no competing interests.
